Color photography



Patented Oct. 6, 1931 UNITED STATES PATENT OFFICE JOHN NAISH GOLDSMITH, OF LONDON, AND THOMAS THORNE BAKER, OF HATCH END,

7 ENGLAND, .ASSIGNORS TO SPICERS LIMITED, OF LONDON, ENGLAND, A BRITISH COMPANY COLOR PHOTOGRAPHY No Drawingl Application. filed .Tune 20., 1930, Serial No. 462,697, and in Great Britain July 30, 1929.

This invention consists in improvements in or relating tocolor photography, and particularly to the production of photographic it is possible to isolate the surface layer from films which carry a "reseau or multicolor screen as well as a sensitized emulsion. Filmsof this type can be used for taking photographs, or for reproduction of'photographs or for cinematograph films in natural colors;

By means of the process described in copending application Serial No. 345604 L.

Dufay, filed 8th March, 1929, successful results have been achieved in applying the multicolor screen to a film made of cellulose acetate composition.

The object of the present invention is to enable the multicolor screen to be successfully applied to cinematographic films of various kinds, including films made from celluloid, from cellulose nitrate, from viscose and the like.

Taking the simple case where a film is to receive (1) A dye of one color, say green; (2) A series of lines of a resist (such, for example as fattyink) Treatment with a bleaching or color-discharging liquid; (4) A dye with another color in the spaces thus bleached; a further object of this invention is to ensure that the dyed zones of the film shall be such that the discharge of color therefrom, and the application of another color, shall be readily accomplished without creeping under the resist lines, and without masking of one color by another so that, in fact, the separate color ele-- ments are clearly distinct and have their proper color values. Another object is to ensure uniformity of the color value or intensity from side to side of each line of color.

According to this invention, it has been found that with any given base (i. e. with a supporting film which may be celluloid, cellulose, cellulose nitrate or other ester or ether of cellulose) and where a special surface layer is to be used which is to receive the dyes," and from which dye can be discharged,

the base by an intermediate layer or septum.

According to the invention a film of celluloid, viscose, cellulose nitrate or other ester scrap commercialfihn, in acetone.

or ether of cellulose is prepared for color photography by coating the basicfilm with a layer of isolating material, then with a surface layer of a material amenable to dyes and to discharging agents, and applying to the film thus prepared a multicolor screen.

According to the feature of the invention .in other words to inhibit the penetration of dyeing agents or discharging agents intothe fihn base. The isolating layer may be produced from a solution of. cellulose acetate with or without added agents such as plasticizing agents; again, the isolating layer may be a condensation product of formaldchyde and phenol or thiourea, or it may be a Varnish or coating of other synthetic resin.

The following is a description by way of example of one method of carrying this invention into effect in making a cinematograph film in natural colors with a base of celluloid.

The celluloid fihnispassed round a roller I which dips into a bath containing a 14-15% solution of cellulose acetate in acetone with sufiicient' plasticizers (i. e. about 56%) to prevent the dry film from curling. By this means a'coating of cellulose acetate whose thickness is of the order of from 48,LL may be applied to the surface of the celluloid film. If the 15% solution of cellulose acetate is found to be too viscous, its viscosity may be reduced by addition of further quantities of solvent. The cellulose acetate solution may, if desired be prepared by dissolving cellulose acetate film, such for example as In thismanner the desired quantity of plasticizers will be incorporated in the solution.

ink to dry washed with water Further there may be added to the solution of cellulose acetate higher boiling solvents, such as cyclohexanone.

When this acetate film is dry the film is passed again through a film-coating machine and there is applied thereto a fine coating (surface layer) of collodion. Conveniently, this surface layer contains one of the dyes, for example a green dye such as malachite green.

. Now proceeds the process of applying the reseauor multicolor screen.

The film (the surface layer of which is dyed uniformly green all over) is then led through a printing machine by means of which extremely fine parallel lines of a resist (such, for example, as a greasy ink) are printed upon it. The rinting may be effected by means of a sma l engraved steel roller having (in one case) 15 lines and 15 intervening grooves per millimetre. The film at this stage exhibits 15 clear green lines and 15 opaque greasy lines (green underneath) per millimetre, both kinds of lines being of about the same width. After an interval to let the ink d the film is led in succession (a) over a bat which bleaches and dissolves out the green d leaving unattac ed the green lines protected by the ink; (b over an inking roller which applies a red ye to the spaces between the ink lines, after which the film is thoroughly to remove excess of dye; (0) through a solvent cleansing bath of benzene to IQII'IOWB the ink lines, leaving exposed the clear green lines.

The film is again led (when dry) through the printing machine which produces parallel lines of a resist (such as reasy ink) as before, but this time at right angles to those formerly made. After an interval for the the film is led in succession (0.) over a bath which bleaches and dissolves o1 t the 'red and green dye from only the cle: r spaces between the greasy lines, (Z1 over an inking roller which applies a violet ye which dyes the interline spaces, and (a) through a solvent cleansing bath of benzene. The film is then dried, is coated with a suitable substratum and is thereafter coated with a layer of sensitized emulsion (a panchromatic emul-' 1. A method of preparing a film comprising a cellulose derivative for color photography which comprises coating the film base first with an isolating material to inhibit the penetration of solutions of dyes and dis-v penetration of solutions of dyes e from only the clear spaces, 5

which comprises coating the film base first with an isolating material to inhibit the penetration of solutions of dyes and discharging agents into the film base, then with a surface layer of a material amenable to dyes and to discharging agents, and finally applying to the said surface layer of the film thus prepared a multi-color screen.

3. A method of preparing a film comprising celluloid for color photography which comprises coating the film base first with an isolating material to inhibit the penetration of solutions of dyes and discharging agents into the film base, then with a surface ayer of a material amenable to dyes and to discharging. agents, and finally applying to the said surface layer of the film thus prepared a multi-color screen.

4. A method of preparing a film comprising a cellulose derivativefor color photography which comprises coating the film base first with an isolating material to inhibit the and discharging agents into the film base, then with a surface layer of a solution of a cellulose derivative which is amenable to dyes and to discharging agents, and finally applying to the said surface layer-of the film thus prepared a multi-color screen.

5. A method of preparin a film comprising a cellulose. derivative or color photography which comprises coating the fi m base first with an isolating material to inhibit the penetration of solutions of dyes and discharging agents into the film base, then with a surface layer of collodion, and finally ap plyingto the said surface layer of the film thus prepared a multi-color screen.

6. A method of preparing a film comprising a cellulose derivative for color photography which comprises coating the film base first with a solution of cellulose acetate, then with a surface layer of a material amenable to dyes and to discharging agents, and finally applying to the said surface layer of the film thus re ared a multi-color screen.

7. A method 0 preparing a film comprising a cellulose derivative for color photography which comprises coating the film base first with a solution of cellulose acetate containing plasticizers, then with a surface liiyelr1 of a material ameimfziblelito dyes and to isc ar 'ng agents, an na y a l in to the said surface layer of the filni fihiis %reared a multi-color screen.

8. A- method of preparing a celluloid film for color photography, which com rises first applying to the film a solution 0 cellulose acetate in acetone containing plasticizers so as to obtain an isolating coating of cellulose acetate of thickness from 4-8;, then appl ing a surface layer of collodion, and final y applying to the said surface layer of the film thus prepared a multi-color screen.

9. A method 'of preparing a celluloid film for color photography, which comprises first applying to the film a 15% solution of cellulose acetate inacetone containing plasticizers so as to obtain an isolating coating of cellulose acetate of thickness from 18y., then applying a surface layer of collodion, and finally applying to the said surface layer of the film thus prepared a multi-color screen.

10. A method of preparing a celluloid film for color photography, which comprises first I applying to the film a 15% solution of cellulose acetate in acetone containing 5-6%' of plasticizers, then applying a surface layer of collodion, and finally applying to the said surface layer of the film thus prepared a multi-color screen.

11. A method of preparing a film comprising a cellulose derivative for color photography which comprises coating the film base first with an isolating material to inhibit the penetration of solutions of dyes and discharging agents into the film base; then applying a surface layer of a material amenable to dyes and to discharging agents, and finally applying to the said surface layer thus prepared a multi-color screen by a process including the use of dyes, resists and dyedisehargmg agents.

12. A method of preparing a film comprising a cellulose derivative for color photography which comprises coating the film base first with an isolating material to inhibit the penetration of solutions of dyes and discharging agents into the film base, then ap-. plying a surface layer of a solution of a cellulose derivative which is amenable to dyes and to discharging agents, and finally ap plying to the said surface layer thus prepared a multi-color screen by a process in eluding the use of dyes, resists and dye-discharging agents.

13. A method of preparing a film comprising a cellulose derivative for color photography which comprises coating the film base first with a solution of cellulose acetate containing plasticizers, then applying a surface layer of a material amenable to dyes and to discharging agents, and finally applying to the said surface layer thus prepared a. multi-eolor screen by a process including the use of dyes, resists and dye-discharging agents.

14. A film adapted for use in color photography comprising a cellulose derivative base, a layer ofisolating material capable of inhibiting the penetration of dyes and discharging agents into the cellulose derivative base, a surface layer on said isolating layer amenable to dyes and discharging agents carrying a'multi-color screen in which the separate color elements are clearly distinct.

15. A film adapted for use in color photography comprising a celluloid base, anisolating coating of cellulose acetate containing lasticizers, a surface layer on said isolating ayer amenable to dyes and discharging agents carrying a multi-color screen in which the separate color elements are clearly distinct.

16. A film adapted for use in color photography comprising a celluloid base, an isolating coating 48 thick of cellulose acetate containing plasticizers, and a surface layer on said isolating layer amenable to dyes and discharging agents and carrying a multicolor screen in which the separate color elements are clearly distinct.

17. A film adapted for use in color photography comprising a cellulose derivative base, a layer of isolating material capable of inhibiting the penetration of dyes and discharging agents into the cellulose derivative base, and a surface layer of collodion on said isolating layer carrying a multi-color screen in which the separate color elements are clearly distinct.

18. A film adapted for use in color photography comprising a celluloid base, an isolating coating of cellulose acetate containing plasticizers, and a surface layer of collodion on said isolating layer amenable to dyes and discharging agents and carrying a multicolorscreen in which the separate color elements are clearly distinct.

19. A film adapted for use in color photography comprising a celluloid base, an isolating layer of thickness from 4-8;; of cellulose acetate containing 5-6% of plasticizers and a surface layer of collodion on said isolating layer carrying a multi-color screen in which the separate color elements are clearly distinct.

In testimony whereof we have signed our names to this specification. JOHN NAISH GOLDSMITH. THOMAS THORNEBAKER. 

